The "hidden rules" of ball milling

 Corresponding proportioning of the ball mill, so that it can crush minerals to the greatest extent, and meet the requirements of mineral crushing and grinding. The quality of mineral crushing can directly affect the efficiency of milling, and ultimately affect the overflow output of the ball mill. The level of ball loading can directly affect the crushing effect. These parameters are mainly affected by the specifications of the ball mill, the internal structure of the ball mill, and the fineness of the product.

The ball must have sufficient impact force so that the ball has sufficient crushing capacity to handle the material, which is directly related to the diameter of the steel ball.

The number of impacts of loading the ball must be enough so that the ball can crush the material. The average ball diameter and filling rate are the main influencing factors. The amount of filling is fixed. In order to ensure sufficient impact force, the diameter of the sphere can be reduced and the number of spheres can be increased to increase the number of impacts on the mineral and improve the crushing efficiency.

To ensure sufficient time for the material to grind in the mill, the ball must have the ability to control the flow rate to ensure that the material is fully crushed.

The law of two-level ball allocation

The use of two spheres of different specifications for grading is called two-stage grading, but there is a requirement that the diameters of the two spheres differ greatly. Its main function is to improve the impact capacity and the number of impacts of the mill. In addition, the higher bulk density allows the material to be fully ground.

In the two-stage ball distribution rule, the large balls are mainly used to crush materials, and the small balls are mainly used to fill the gaps of the large balls to increase the bulk density of the balls, thereby controlling the flow rate of the flow, thereby increasing the grinding The second is the transfer of energy; the last is to squeeze the coarse-grained materials in the gap into the impact area of ​​the big ball.

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∅The realization of 4.5mx6m overflow ball mill electric control system

Overflow https://clactononseaessex.uk are widely used in cement, mining and thermal power generation industries due to their simple operation and low maintenance costs. With the development of society, the ball mill has made great progress in overall performance. The ball mill electrical control system is the central system of the entire ball mill, used to control various operating techniques.

  The control system mainly includes:

(1) Control of temperature measurement of bearings and stator windings;

Each mill has three temperature measurement points for the main bearing at the feed end, the main bearing at the discharge end and the stator winding of the main motor, and the pinion bearing and the main motor have two temperature measurement points. At the same time, the status value of each point can be displayed in real time on the man-machine interface connected to the PLC, and the alarm value and shutdown value of each measurement point can be given.

(2) Control of the main bearing high and low pressure lubrication station

   The main bearing high and low pressure lubrication station includes high pressure oil supply and low pressure lubrication. The high pressure oil supply system of each station supplies two high pressure pump motors. When any high pressure pump fails to work or the oil pressure is low, the backup pump will automatically replace the original work. The pump works and continues to supply oil to the main bearing.

(3) Pressure control

The high-pressure system of the lubrication station is equipped with four pressure sensors to detect the high-pressure oil supply system in real time. When the oil pressure is lower than the lower limit setting value, the sensor will send out an audible and visual alarm signal and limit the start of the host; when it is higher than the upper limit value When the sensor will send out an audible and visual alarm signal.

(4) Oil flow control

Install a flow switch in the low pressure oil supply system near the two main bearing oil supply points to continuously monitor the oil supply flow at each point.

(5) Oil temperature control

There is no electric heater or cooler on the lubrication station, and the oil temperature is given an obvious display signal by the bimetal thermometer through the electric control system to automatically turn on the electric heater or the cooling water valve.

(6) Control of slow drive motor

The slow-speed drive motor and the main motor are interlocked with each other, and they cannot work at the same time; when the slow-speed drive motor is working, the high-voltage oil supply system should be in a normal working state.

Choosing the Right Ball Mill Feeders

Three types of ball mill feeding device configuration methods: drum feeder, combined feeder and feeding trolley.

1. Drum feeder

Drum feeder

(a) The materials are pushed into the feeding port through the spiral plate to realize compulsive feeding.

(b) The specially designed anti-spitting small cone effectively solves the problem of material leakage.

(c) It is suitable for use with a single spiral classifier or cyclone. It has a simple structure and is easy to use without maintenance.

2. Combined feeder

Combined feeder

(a) Keep feeding from a high position, no backflow and overflow, reduce labor intensity. Avoid pollution and improve efficiency.

(b) It is suitable for use with double spiral classifier.

3. Feeding trolley

Feeding trolley

(a) The trolley can move back and forth on the track, and the feed elbow can be directly inserted into the feed inlet.

(b) It connects the flange and the feeding device (silo or feeder).

(c) It has simple structure which is convenient to maintain. This device is suitable for large mills above 32.